I notice that most game challenges are offered without any handicaps. When these games are played, how does the system bump up or down anyone’s level? Won’t the result be skewed if, say, a stronger player beats a weaker player, but no handicap was given?
I believe that OGS employs a rating system similar to that of chess, so a stronger player with a higher rating earns less points for beating a weaker player with a llower rating. On the other hand if you beat a stronger player with a higher rating then you earn more points and the opposing player lose more points.
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The ranking system does some more magic to achieve better results, but what Woden wrote is in almost all cases correct.
AdamR wrote some more aspects of the rating system down in this post:
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So does this mean that, regarding ranking, it doesn’t matter whether I play with a handicap? Say I play a game with someone 6 stones stronger than me, with no handicap given. It’s not whether I win or lose, it’s by how much?
As I understand it, if you play someone 6 stones stronger than you with 6 handicap stones then the outcome will affect both your ranks as if you had played someone of the same rank in an even game. However; If you play without handicap stones then the stronger player has to win for a microscopic increase in rank and risks a large decrease if they loose. This is simply a reflection of the odds being massively in their favour. Similarly you will suffer only a slight decrease from loosing as expected but will gain a large increase from winning an even game against the odds.
Nb. The ranking system is a very complicated ‘best-fit’ statistical process that makes it virtually impossible to look at a game in isolation.
“No game is an Island, entire of it self; every game is a piece of the Continent, a part of the main.”
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No, it never matters by how much you win or lose.
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Glcko2 (the rating system) only uses win/lose to calculate the new rank. It does not take into account by how many points you win/lose, only the difference in your ranks matters.
As far as I understand it, the same is right for games with handicap, since Glicko2 only handle win/lose(/draw) for calulation and current rating. Therefore it would push both players ranks hard, when the game was played with high handicap and the “weaker” player wins.
@Kosh have you a deeper insight, how ogs implements Glicko2? I found no official statement about the treatment of games with handicap when ranks are calculated.
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Nope.
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This was the announcement when Glicko-2 was launched: OGS has a new Glicko-2 based rating system!
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I found no official statement about the treatment of games with handicap when ranks are calculated.
Me neither ! Does anyone have any information about this ?
Last weeks, I only played handicap games, and I have the impression that the OGS ranking system does not take handicap into account.
If that’s true, it means that it’s really flawed for ranked handicap games. If you play against a very weaker opponent, with the correct handicap, the ranking system will punish you for loosing although the very purpose of handicap is to giving you a 50% to win or loose…
It’d be great to have the confirmation about this from a developer or staff member.
Based on looking at the front-end source code, an effective rating is calculated for black using a handicap adjustment.
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1 stone = 1 rank. If blacks rank is 17k and black has 5 stones handicap, blacks rank is treated as 12k when the new rank is calculated.
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I see, thanks.
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Is that assumption the same regardless of the board size?
On 9x9 handicap is a combination of komi and stones. Handicap 4 shouldn’t be 4 stones on the board.
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I see. That’s helpful, thanks.
For what it is worth.
Here is the unofficial handicap system we use in Nijmegen.
It is a “class difference - handicap - komi for white” table for 19x19, 13x13 and 9x9.
Negative komi: white has to give komi.
You can find the complete table here.
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Interesting, thanks for sharing that.
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Here is a comparison of some different handicap systems in use on 9x9 (including the Nijmegen system) [2021 Rating and rank adjustments - #528 by gennan]
AFAIK there is no international standard.
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